Purpose: The principal aim of this project was to investigate the influence of clinical indices of injury severity and polymorphism of the apolipoprotein E gene upon the long-term physical, cognitive and emotional sequelae of traumatic brain injury and spontaneous subarachnoid haemorrhage. It was also intended to determine the extent to which changes occur in these sequelae beyond the initial six months post injury. Method: Sixty-two brain injury patients who had previously taken part in a neuropsychological assessment at six months post injury were traced and participated in a follow-up assessmens some 6-9 years subsequent to their injury. Separately, a group of 70 subarachnoid patients drawn from a consecutive series of neurosurgical admissions participated in a neuropsychological assessment at 14 months subsequent to their haemorrhage. In both studies, the assessment comprised a semi-structured interview and a battery of cognitive measures focusing principally upon memory and executive function tasks. A questionnaire including a range of standardised measures of anxiety, depression and quality of life was left with patients to be returned by post. Results: The ApoE e4 allele did not appear to influence recovery amongst these brain injury survivors, though there are suggestions that it may have an influence upon subgroups of patients. Amongst traumatic brain injury survivors, post-traumatic amnesia was a better predictor of functional or emotional outcome than consciousness based measures. However, consciousness based measures were more predictive of cognitive sequelae and low admission Glasgow Coma Scale was associated with continued improvement on information processing tasks. Other than on these tasks, there was little evidence of change between 6 months and 6-9 years post injury. Amongst the subarachnoid haemorrhage patients, Fisher Grade was found to be more predictive of subsequent Glasgow Outcome Scale and cognitive function than WFNS Grade or other clinical indices. Surviving aneurysmal patients had comparable levels of recovery to patients who had a negative angiogram. In both studies emotional sequelae, in particular anxiety-related difficulties, were found to be a principal factor in the functional outcome of some 40% of patients. Conclusions: Greater emphasis should be placed upon measures of post-traumatic amnesia as predictors of functional recovery in surviving patients. The use of an amnesia measure may also be warranted in studies of outcome following subarachnoid haemorrhage or other stroke. The ApoE e4 allele does not appear to have a strong influence upon functional recovery after brain injury across all patients, though it is possible that it interacts with other factors to influence recovery in subgroups. Greater emphasis should be placed upon the prevention and/or detection and treatment of mood disorders following brain injury. In the absence of intensive rehabilitative interventions, survivors of serious brain injury are more likely to deteriorate than to continue to recover beyond six months post injury.